Mellat Park, Vali Asr Avenue, Tehran, Iran
Objectives- This research was performed to assess systolic and diastolic left ventricular function in patients with ventricular and AV sequential pacing, placing particular emphasis on the long-term evaluation of left ventricular function in ventricular and AV sequential pacing.
We also compared the short-term effects of different modes of pacing on LV function.
Methods- We conducted a prospective one-year echocardiographic study on 40 patients with ventricular and AV sequential pacemakers at our center in Tehran. Echocardiography was done before and 1 week, 2, 6 and 12 months after pacemaker implantation. Systolic and diastolic functions were assessed as well.
Results- 12 (30%) women and 28 (70%) men aged 65.32±13.11 years were recruited in the study. 32 (80%) had advanced AV block and 8 (20%) had sick sinus syndrome. End diastolic volume, stroke volume, and ejection fraction were significantly decreased (p<0.01) in ventricular pacing group in short and long–term evaluations. In AV sequential pacing group, end diastolic volume, end systolic volume, and stroke volume were significantly decreased (p<0.01 for both).
Conclusion- In spite of a decreased ejection fraction, ventricular pacing can improve cardiac output both in short and long-terms, but AV sequential pacing improves cardiac output by increasing both ejection fraction and the heart rate. Diastolic function assessment by echo is not as reliable as in systolic function